Assessment of Biodiversity at Different Stages of the Forest Cycle George Smith1, Tom Gittings2, Mark Wilson2, Laura French1, Anne Oxbrough2, Saoirse O’Donoghue1, Josephine Pithon2, Vicki O’Donnell3, Anne-Marie McKee1, Susan Iremonger1, John O’Halloran2, Daniel Kelly1, Fraser Mitchell1, Paul Giller2, Tom Kelly2 1 BIOFOREST Project, Department of Botany, Trinity College Dublin 2 BIOFOREST Project, Department of Zoology, Ecology and Plant Science, University College Cork 3 Coastal and Marine Resources Centre, University College Cork FINAL REPORT, FEBRUARY 2005 University College, Cork University of Dublin, Trinity College Project 3.1.2 Report CONTENTS 1 INTRODUCTION.......................................................................................................... 3 1.1 CONTEXT .................................................................................................................... 3 1.1.1 The concept of biodiversity .................................................................................. 3 1.1.2 Forest biodiversity and policy development in Ireland........................................ 5 1.1.3 Existing information on forest plantation biodiversity in Ireland ...................... 6 1.1.4 Need for the present study................................................................................... 6 1.2 OBJECTIVES................................................................................................................. 6 2 SURVEY DESIGN AND DATA ANALYSIS............................................................ 7 2.1 SELECTION OF FOREST TYPES AND AGE CLASSES ..................................................... 7 2.1.1 Forest type ........................................................................................................... 7 2.1.2 Age classes ........................................................................................................... 7 2.1.3 Survey objectives ................................................................................................. 8 2.2 SURVEY STRATEGY ..................................................................................................... 8 2.2.1 Age classes ........................................................................................................... 8 2.2.2 Geography and environment ............................................................................... 9 2.3 SITE SELECTION ........................................................................................................ 10 2.3.1 Desktop .............................................................................................................. 10 2.3.2 Field ................................................................................................................... 10 2.4 CHARACTERISATION OF BIODIVERSITY................................................................... 11 2.4.1 Taxonomic groups ............................................................................................. 11 2.4.2 Species richness ................................................................................................. 11 2.4.3 Species diversity ................................................................................................ 12 2.5 DATA ANALYSIS....................................................................................................... 13 2.5.1 Data organisation .............................................................................................. 13 2.5.2 Statistical tests................................................................................................... 13 2.5.3 Analysis of assemblage structure....................................................................... 14 2.5.4 Identification of indicators................................................................................. 14 3 GIS DATABASE AND DESCRIPTION OF STUDY SITES ................................ 16 3.1 INTRODUCTION........................................................................................................ 16 3.2 METHODS ................................................................................................................. 16 3.2.1 Data acquisition................................................................................................. 16 3.2.2 Construction of GIS database............................................................................ 19 3.3 RESULTS.................................................................................................................... 21 3.3.1 GIS database ...................................................................................................... 21 3.3.2 Site descriptions................................................................................................. 23 3.3.3 Site management ............................................................................................... 28 3.3.4 Stand structure.................................................................................................. 31 3.4 DISCUSSION.............................................................................................................. 38 3.4.1 Comparison of ash and Sitka spruce sites.......................................................... 38 3.4.2 Trends in afforestation and land use ................................................................. 39 3.4.3 Environmental changes over the forest cycle..................................................... 39 3.5 CONCLUSIONS.......................................................................................................... 39 4 VEGETATION.............................................................................................................. 41 4.1 INTRODUCTION........................................................................................................ 41 4.1.1 Importance of forest flora................................................................................... 41 4.1.2 Forest cycle and plant diversity......................................................................... 41 BIOFOREST PROJECT i Project 3.1.2 Report 4.1.3 Comparison of conifer and broadleaf plantations .............................................. 41 4.1.4 Diversity indicators........................................................................................... 42 4.2 METHODS ................................................................................................................. 43 4.2.1 Fieldwork methods............................................................................................. 43 4.2.2 Species identification ......................................................................................... 44 4.2.3 Data organisation .............................................................................................. 45 4.2.4 Data analysis ..................................................................................................... 46 4.3 VEGETATION RESULTS............................................................................................. 48 4.3.1 Ordination of forest stands................................................................................ 48 4.3.2 Measuring vegetation diversity......................................................................... 55 4.3.3 Trends in species richness and diversity ........................................................... 57 4.3.4 Structural groups .............................................................................................. 60 4.3.5 Diversity indicators across the structural cycle ................................................ 65 4.3.6 Diversity indicators within the structural groups ............................................ 73 4.3.7 Species indicators............................................................................................... 79 4.4 DISCUSSION.............................................................................................................. 88 4.4.1 Overview of results............................................................................................ 88 4.4.2 Vegetation composition ..................................................................................... 89 4.4.3 Effects of site history and surrounding land use ............................................... 90 4.4.4 Biodiversity indicators....................................................................................... 91 4.5 CONCLUSIONS.......................................................................................................... 94 4.5.1 General conclusions........................................................................................... 94 4.5.2 Biodiversity indicators....................................................................................... 94 4.5.3 Management recommendations......................................................................... 95 4.5.4 Modifications to the Forest Biodiversity Guidelines ......................................... 96 5 SPIDERS ........................................................................................................................ 97 5.1 INTRODUCTION........................................................................................................ 97 5.2 METHODOLOGY ....................................................................................................... 98 5.2.1 Sampling protocol.............................................................................................